Why do Crabs Walk Sideways? Learn about these funny crustaceans…

Crabs have characteristics in their anatomy that makes them move in a peculiar way. Their evolving process, anatomy,  and habitats are deeply related to such fact.

Why  do Crabs Walk Sideways.?  The main reason of this fact lies in their legs, which are attached to their body’s sides . Moreover, their articulations bend outwards enabling them to displace sideways only. There are few species of crabs that are able walk forward. This fact allows them to enter small holes and cracks to stay away from fish with sharp teeth and larger crabs.

Main Reasons about Why do Crabs Walk Sideways? 🦀

Over time, the crabs’  anatomy has evolved , resulting in a transformation of their shells, which gives a wide and short shape to their bodies. On the other hand, their belly is narrow and small. These aspects have caused that each one of their legs be located  in a longitudinal position, that is to say,  they are on each side and end of the body.

This is the main   reason why crabs tend to make lateral movements to displace more easily in the different habitats where they develop.

Therefore, the big advantage that crabs have by walking in such a way, is that they can move with ease on rocky or unstable surfaces such as water bottoms .

Since crabs aren´t   great swimmers, they need to walk through different surfaces including, sand, rocks and even some species reach to climb palm trees. (See our article coconut crabs)

Let´s watch them…


It´s   important to highlight that their anatomy has many aspects that really worth to study . But in this article,  we´ll focus on  what refers to their legs and the reasons why they move in such a way. First of all it should be mentioned that crabs have ten legs, (decapods) distributed on each side of their body.

The first pair is located in the front part of their body, and has evolved fulfilling the role of pincers, which provides them  a tool  to hunt and defend against possible threats. We can also mention the case of the fiddler crab that has a front clamp larger than the other.

Another aspect of their  anatomy that makes them walk sideways, is their exoskeleton that serves as a shell that covers and protects their bodies. Therefore, it´s much easier for them to move sideways, taking into account the size of their shells. Although these characteristics influence their gait, crab still have the ability to rotate their bodies if necessary.

In turn, with these movements aside, the crabs prevent what would be the exposure and vulnerability of the defenseless and most sensitive areas of  their bodies.

 why do crabs walk sideways: crabs anatomy

Common Habitats

To understand the reasons why crabs walk sideways, we must also study the habitats where they develop. In terms of their evolution,  this aspect is one  of the reasons why they have adapted to walk in side movements. The main habitat of the crab is water, whether it is sweet or salty, and apart from water, the surroundings where they can find food, be it the shore of a beach or the river basin.

According to every species,  they may inhabit in rivers, streams or lagoons as  the case of the blue crab or even in the main seas. The peculiarity of this animal is that although it develops in the water, it´s  not a great swimmer like other aquatic species, and because of such fact it has had to adapt to the soil of these environments. For example, in the case of crabs that inhabit the sea, they adapt their steps and movements , to displace ar ound the sand, some rocks and palm trees.

On the other hand, in the case of crayfish , they have to adapt their movements to lakes, wet rocks and even the land where they can also get their food. Now, it is known that the main reason why crabs walk sideways is due to their morphology, but we must not forget the adaptations that had to be made in relation to the environment, and the advantages they represent on these surfaces. There is no doubt that all the creatures of the world have interesting andsometimes weird features, that really worth to discover.

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